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cpu/intel/common: Extend FSB detection to cover TSC 

Use the same CPUID switch block to resolve the multiplier
to derive TSC from FSB/BCLK frequency.

Do not return 0 as base frequency.

Change-Id: Ib7f1815b3fac7a610f7203720d526eac152a1648
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/31340
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
This commit is contained in:
Kyösti Mälkki 2019-02-11 10:12:35 +02:00 committed by Patrick Georgi
parent 5a157176dd
commit ecea91679f
1 changed files with 54 additions and 16 deletions
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70
src/cpu/intel/common/fsb.c
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@ -14,6 +14,7 @@
#include <arch/early_variables.h>
#include <cpu/cpu.h>
#include <cpu/x86/msr.h>
#include <cpu/x86/tsc.h>
#include <cpu/intel/speedstep.h>
#include <cpu/intel/fsb.h>
#include <console/console.h>
@ -21,15 +22,18 @@
#include <delay.h>
static u32 g_timer_fsb CAR_GLOBAL;
static u32 g_timer_tsc CAR_GLOBAL;
static int get_fsb(void)
/* This is not an architectural MSR. */
#define MSR_PLATFORM_INFO 0xce
static int get_fsb_tsc(int *fsb, int *ratio)
{
struct cpuinfo_x86 c;
static const short core_fsb[8] = { -1, 133, -1, 166, -1, 100, -1, -1 };
static const short core2_fsb[8] = { 266, 133, 200, 166, 333, 100, 400, -1 };
static const short f2x_fsb[8] = { 100, 133, 200, 166, 333, -1, -1, -1 };
msr_t msr;
int ret = -2;
get_fms(&c, cpuid_eax(1));
switch (c.x86) {
@ -37,53 +41,75 @@ static int get_fsb(void)
switch (c.x86_model) {
case 0xe: /* Core Solo/Duo */
case 0x1c: /* Atom */
ret = core_fsb[rdmsr(MSR_FSB_FREQ).lo & 7];
*fsb = core_fsb[rdmsr(MSR_FSB_FREQ).lo & 7];
*ratio = rdmsr(MSR_EBC_FREQUENCY_ID).lo >> 24;
break;
case 0xf: /* Core 2 or Xeon */
case 0x17: /* Enhanced Core */
ret = core2_fsb[rdmsr(MSR_FSB_FREQ).lo & 7];
*fsb = core2_fsb[rdmsr(MSR_FSB_FREQ).lo & 7];
*ratio = rdmsr(MSR_EBC_FREQUENCY_ID).lo >> 24;
break;
case 0x25: /* Nehalem BCLK fixed at 133MHz */
ret = 133;
*fsb = 133;
*ratio = (rdmsr(MSR_PLATFORM_INFO).lo >> 8) & 0xff;
break;
case 0x2a: /* SandyBridge BCLK fixed at 100MHz */
case 0x3a: /* IvyBridge BCLK fixed at 100MHz */
case 0x3c: /* Haswell BCLK fixed at 100MHz */
case 0x45: /* Haswell-ULT BCLK fixed at 100MHz */
case 0x4d: /* Rangeley BCLK fixed at 100MHz */
ret = 100;
*fsb = 100;
*ratio = (rdmsr(MSR_PLATFORM_INFO).lo >> 8) & 0xff;
break;
default:
return -2;
}
break;
case 0xf: /* Netburst */
msr = rdmsr(MSR_EBC_FREQUENCY_ID);
*ratio = msr.lo >> 24;
switch (c.x86_model) {
case 0x2:
ret = f2x_fsb[(msr.lo >> 16) & 7];
*fsb = f2x_fsb[(msr.lo >> 16) & 7];
break;
case 0x3:
case 0x4:
case 0x6:
ret = core2_fsb[(msr.lo >> 16) & 7];
*fsb = core2_fsb[(msr.lo >> 16) & 7];
break;
default:
return -2;
}
break;
default:
return -2;
}
return ret;
if (*fsb > 0)
return 0;
return -1;
}
static int set_timer_fsb(void)
static void resolve_timebase(void)
{
int ret = get_fsb();
int ret, fsb, ratio;
if (ret > 0) {
car_set_var(g_timer_fsb, ret);
return 0;
ret = get_fsb_tsc(&fsb, &ratio);
if (ret == 0) {
u32 tsc = 100 * DIV_ROUND_CLOSEST(ratio * fsb, 100);
car_set_var(g_timer_fsb, fsb);
car_set_var(g_timer_tsc, tsc);
return;
}
if (ret == -1)
printk(BIOS_ERR, "FSB not found\n");
if (ret == -2)
printk(BIOS_ERR, "CPU not supported\n");
return -1;
/* Set some semi-ridiculous defaults. */
car_set_var(g_timer_fsb, 500);
car_set_var(g_timer_tsc, 5000);
return;
}
u32 get_timer_fsb(void)
@ -94,10 +120,22 @@ u32 get_timer_fsb(void)
if (fsb > 0)
return fsb;
set_timer_fsb();
resolve_timebase();
return car_get_var(g_timer_fsb);
}
unsigned long tsc_freq_mhz(void)
{
u32 tsc;
tsc = car_get_var(g_timer_tsc);
if (tsc > 0)
return tsc;
resolve_timebase();
return car_get_var(g_timer_tsc);
}
/**
* @brief Returns three times the FSB clock in MHz
*